His rich experience on the stage, in local productions such as Ogu,[2] later made Oh an in-demand character actor on the big screen.

[3] Oh has starred in numerous successful films, in roles such as the owner of the organized crime-funded private jail in Oldboy (2003), a former gang boss in Mapado (2005), a weapons smuggler in A Bittersweet Life (2005), a transvestite in Foxy Festival (2010), a Chinese-Korean conman in The Thieves (2012),[4] and a sympathetic inmate in Miracle in Cell No.

[6] In March 2018, Oh was dropped from Along with the Gods: The Two Worlds due to sexual harassment allegations.

[8] In 1987, Oh was arrested and detained for three days for protesting at the June Democratic Struggle.

[14][15] The following day, actress Uhm Ji-young came forward in JTBC's Newsroom, saying that she was also sexually harassed by Oh in 2003.